Projectile



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As. M. ZANDMER l PROJECTIL 4 Sheets-Sheet 2 Filed Dec. 14, 1942 Aug 33?193484 s. M. ZANDMER l 2,448,343

PROJECTILE Filed Dec. 14, 1942 4 Sheets-Sheet 3 Aug., 3l, i948. s. M.ZANDMER 2,4489343 PROJECTILE Filed Deo. 14, 1942 .4 sheets-sheet 4 Y gm,In \\Y\\ \\\-k l alas ymrvamwner;

Patented Aug. 31, 1943 UNI TED S TA'ifES PATENT OFFICE PROJECTILE- vSolis Myron Zandmer, Los Angeles, Calif.

Application December 14, 1942, Serial No. 468,971

The invention relates to improvements in a projectile and barrel or boreof a gun or `cannon r other firearm.

An object of the invention is the provision of means. to reduce thefriction and loss of energy in the passage of the projectile through thebore of the cannon while utilizing spiral tracks, grooves, or guides inthe bore to impart a rotary motion or spin to the projectile Anotherobject is to provide a positively interconnected friction reducingspirally disposed guiding means between the projectile and the barrel orcannon bore, positively constraining it to a rot'arymotion in itspassage through the cannon,

Another object is to provide for a substantial reduction of recoil byreason of the provisiony of the friction-reducing means according to theinn vention, thereby permitting of lighter, simpler, and more mobileconstruction of guns or cannon and of recoil mechanism, especiallydesirable for tank or aircraft cannon, which can consequently beof'larger size.

A further object is the provision of means pro viding for frictionreduci-ng bearings at more than one point along the yprojectile and alsoto provide mea-ns enabling change in the rate of the spiral of ther-iiiing in the barrel of the cannon to change the rate of spin orrotary motionof the projectile.

4Other objects will appearhereinafter.

2Enthe drawings which are diagrammatic Figure 1 is, a small scale viewof a projectile according to the invention in which balls are mounted.

Fig. 2 is an enlarged fragmentary section on line 2 2 of the projectileof Fig-l, in place in the barrel of the firearm Aalso shown in section.

Fig. 3 is an enlarged view of a ball between the projectile and bore.

Fig. 4 is a view of a projectile embodying a preierredv modification ofthe'inventi-on, and Fig. 5 is an enlarged section on line 5-5 of Fig. 4,also showing the barrel of the lrearm in section.

Fig. 6 is -a view of a projectile embodying a further modication, andFig. '7 is a section on line 1*-1 of Fig. 6, and also showing the barrelof the rearmin section.

Fig. 8V is a sectional View showing a detail.

Fig. 9 is an enlarged sectional view of a modificat-ion ofthe ballmounting in the projectile, and Fig;` 10 is another view of the sameshowing the balli received in and engaging the spiral groove or track inthe bore of the cannon or firearm,

Fig.11 is a view similar to Fig. 9 showing the ball received in thespiral groove diagrammatie cal-ly shown.

Fig. i2 is a top plan View of the ball mounting of Fig. 9.

Fig. i3 is an enlarged sectional View of a iurtlier modification of; theball mounting in the projectile, and Fig, 14 is another View of the sameshowing the ball received in the spiral groove or track in the `boreofthe cannon or rearm.

Fig. 15 is a view similar to Fig- 13 showing the ball received in thespiralv groove. diagrammatically shoWn. y

Fig. 16 is a top plan view of the ball mounting of Fig. 13.

Fig.' 17 is a diagrammatic illustration of r`aportion of a irea'rm'borelaccording to the invention, provided with spirally disposed tracks,grooves, or guides for receiving the balls of the projectile and forimparting a rotary motion thereto.

Fig,e 18V is a diagrammatic illustration of an'- ot-her portion' offirearmA bore showing spiral tracks or grooves according to theinvention, disposedin increased rate of spiral.

Fig. 119 -isareduced view similar to Fig. 8 of a desirable modification.

In the drawings i represents a projectile in which, according to theinvention, spaced apart bal-ls 2v `are mounted in seats or sockets atfixed positions or locations in the body ofthe projectile, and aremounted to permit them to rotate in said seats or sockets 3 in theprojectile. l

The balls may be mounted in the body of the projectile in the seats orsockets 3 provided in any suitable way and by any suitable means, and inthe embodiment shown cages or insert members or plugs 4, having thesockets 3 formed thereon, are employed inserted in recesses 5 formed inthe body of the projectile.

The cages providing sockets or seats 3 in the projectile are designed toreceive a portion ofthe entire surface of the balls 2, While leaving a-portion of the balls exposed and protruding fromand beyond `the surfaceof the projectile. The portion off the sur-face of the ball received inthe seat or socket, and the remaining portion protruding from the bodyofthe projectile may be substantially half or more or any portion lessthan 4half of the surface vof theball, as may be desired. In thepreferred embodiments exemplified in the drawings the ballsare disposedso that at least one hundred and twenty degree arcuate sections thereofengage in the riing groove and in the yprojectile body, respectively. Inthe form of Figs. l-3 approximately half the ball engages in each. Thesame is true in the form of Figs.

lief), and with respect to the balls 2 in the form of Figs. 6-8 (inwhich the balls 2a are primarily guiding or centering balls, rather thanprojectile rotating balls). In the. form of Figs. 9-12, an arcuate thirdof the ball is engaged in the projectile body and nearly two arcuatethirds of it in the rifling. In the form of Figs. 13-16 an arcuate thirdof the ball engages in the riiling and nearly two arcuate thirds in theprojectile body. By this arrangement effective shear sections and loaddistribution are attained.

In this connection it is desirable to so mount each ball in its seat orsocket, that there is-a minimum of bearing contact between the ballV andits seat or socket, so that there will be a minimum of contact pointsVVof sliding friction bespacing of the balls 2, Fig. 6.

I also provide by my invention for additional bearings on a projectilefor use in a bore having variations in the rate of spiraling of itsgrooves. These additional bearings, additional to the single circularrow of balls in xed spaced location, are provided by means of one ormore rotary rings 8 carrying rotary balls, as indicated at 2a in Figs.6, 7 and 8, the balls 2a having rolling contact on a surface 9 of theprojectile. The rotary ring 8 is designed in any suitable manner tocarry the balls 2a for rotation in fixed spaced locations in said ringcorresponding to the The ring may, for example, be formed in two partsas seen in Fig. 8, comprising an inner ring portion and an outer Y ringportion and so shaped or formed at the tween the ball and its socket asthe ball rotates therein.

Spiral grooves or guides 6 are provided in the,

barrel or bore 'l of the gun sor cannon and are of a suitable shape incross-section, i, e,` arcuate or spherical, to receive and to positivelyguide and constrain ythe balls seated in the projectile, to the spiralpath of the grooves to positively rotate the proj'ect'ne by means of theball bearings moving in engagement with the spiral grooves, upon itsbeing projected through the bore. The smooth portions la of theprojectile between the spaced apart ball bearings are disposed adjacentand to pass over the corresponding smooth portions 'la of `the barrelbetween the spaced spiral grooves and are desirably spaced therefrom bya minimum of clearance sufficient to provide for expansion andcontraction under temperature change While desirably maintaining theminimum of clearance at alltimes. The full load of the projectile in thebore lof the gun is then carried by the balls. However, the invention isnot limited to this, as relative dimensions may be such that the load ofthe projectile may bepartially or Wholly carried by the smooth surfacesla of the projectile slidably engaging the smooth surface portions 'laof the barrel, th-e balls then bearing principally against the sides lofthe spiral grooves to guide and impart rotation to the projectile.

Desirably the Iballs Zfmay be mounted in spaced apart relation in acircular row around the projectile, as seen in Fig. 1, the balls beingdisposed for rotation in the seats or sockets 3 which are spaced apartin said circular row so that the protruding part of each of the ballswill :be in a position such that it will enter one of the spiralgroovesV 6 of the bore 1 `of the cannon or gun. The balls, however, neednot form a circular row, but may be disposed on or along the body of theprojectile in any desired spaced arrangement so that they are in aposition to be received in the spiral grooves in the bore of the gun,which grooves also need not be arranged in any fixed number or relationas to spacing so long as the grooves ,and balls are made and disposed tocooperate.

If the rate of spiraling of the grooves 6 in the bore is uniformthroughout the length of the bore, the ball-s need not be in a circularrow. Also, a second circular row of balls 2V may be provided as rseen inFig. 4 to provide additional bearings and positive guiding means.

If, however, the rate of spiral is changed during the passage throughthebore, only a single circular row or group of rotary balls in xed spacedlocation in the projectile surface may be used as in Fig. 1, which willbe capable of conforming to any change in the rate of spiraling of thegrooves.

ball recesses, as to conform to the spherical surface of and to retainthe balls in the ring for rotation therein. The two parts of the dividedring S may be secured together by any suitable means, as rivets or otherfastening means I0. The projectile surface or raceway 9 for the balls 2aof the rotary ring 3 may `be .provided in any suitable manner, and inthe embodiment shown may desirably be disposed inwardly of the mainsurface I of the lprojectile thereby forming a shoulder at Il againstwhich the rotary ring may have sliding contact. The connection of thenose la: of the projectile to the body thereof, may

e be by a screw threaded connection as indicated at I2 in Fig. 8.Desirably the rotary ring 8 may be initially fixed in position on theprojectile by any temporary fastening and in the embodiment shown asmall frangible spot Weld I3 or other fastening is formed between therotary ring 8 and the shoulder ll, which will be broken upon any changein the rate ofv spiral of the grooves of the barrel in the passage ofthe projectile therethrough, to permit the rotary ring to change itsrotary position in respect to the projectile to conform to the changedrate of spiral of the grooves, the projectile still being positivelyguided in the spiral grooves by the single circular row of balls 2 (Fig.6) in xed location around the projectile whatever the rate of spiral `ofthe grooves may After the temporary seal or fastening i3 is broken, theballs 2a in the rotary ring 8 simply provide bearing for the projectilein its passage in the grooves of the .bore and do not serve to impartany rotary motion to the projectile, said rotary motion being impartedto the projectile by the xed rotary balls 2 in the spiral grooves of thebore. Upon discharge of the projectilefrom the barrel, there is nofurther function for the ring 8 and .balls 2a and whether or not thering 8 -becomes separated from the projectile is immaterial. However,the nose la: may desirably be extended in diameter as shown at Ima: inFig. 19 to hold the rotory ring 8 on the projectile.

.Regarding the mounting of the balls 2 in substantially fixed locationsin the projectile surface, as seen in Fig. 3, the balls 2-may each bedisposed in a `socket or seat 3 desirably of somewhat larger diameterthan the segment of the spherical surface of the ball, at the plane ofcontact between the ball `and seat, which is substantially the balldiameter in the embodiment shown in Fig. 3 .(in which the ball isdisposed substantially half in the socket and half protruding from thesurface of -the projectile and engaged in the spiral grooveof the gunbore). Thus in Fig. 3, the seat 3 is desirably made of larger ldiameterthan that of the ball. The ball preferably is temporarily fastened tothe vbottom of the seat or socket 3.by

the'surface thereof, cages in said recesses for receiving said balls,said recesses being larger in area than said cages,.so th'at the cages.are laterally shiftable. therein, 'and resilient means disposed .insaid recesses 'engaging the'cage members and the walls of the recessesvand retaining said cages ltherein in suchv manner that said cages mayshift irisaid recesses to provide shift of :alignment of said balls toadapt them tothe spaced spiral groovesof the gun bore. 1 1' i.

3. A projectile having a plurality 'of recesses in Vthe surface thereofat spaced intervals around the projectile, a cage member in each of saidrecesses, each recess being of a greater dimension than the associatedcage measured circumferenytiallyV of the projectile, a ball arranged ineach cage member and projecting from the surface of the projectile adistance suiiicient to extend into spaced spiral grooves in the bore ofa gun, and :spring means disposed in said recesses and engaging the cagemembers.

4. In a projectile, spaced proj ectile-rotating means comprising ballsseated for rotation in the vsurface of the projectile and extendingoutwardly from the surface of the projectile suiiiciently for engagingspaced spiral grooves in th'e bore-of a gun, a ring member mounted forrotation on the projectile. during firing thereof, a second groupof-balls mounted in said ring member and spaced Vtherearoundcorresponding to the spacing of the 5 In a projectile, spacedprojectile-rotating means .comprising balls Seated for rotation in thesurface of the projectile and extending outwardly -irom the surface ofthe projectile suiiicientlyI for engaging spaced spiral grooves inthebore of a gun, a ring member mounted for rotation on the projectileduring the ring thereof, a second group of balls mounted in said ringmember and spaced therearound corresponding to the spacing of the firstballs, said-secondA group of balls extending outwardly from the surfaceof the projectile for a distancesufcient for engaging the 'spiralgrooves in the bore of the gun whereby the second group of ballsserveasadditional .ball bearings, the rotative mounting of said-ringen theprojectile providing compensation for any change in the rate of spiralin the grooves ofthe vgun bore, and a frangible connection between thering, member and the projectile for freeing Asaid ring member to rotateduring thering of the projectile when such compensation is required'.

6. In a projectile; a ring member embracing la viis reduced `diameterportion of the projectile and rotatable thereon, balls rotatably seatedin said Vring -member at spaced intervals therearound,

said balls projecting outwardly from the vring member a distancesuicient for engaging spaced spiral grooves inthe bore of a gun, saidprojectile having additional ball means arranged to engage `in suchspaced spiral grooves, and having a frangible connection between thering member and the projectile holding said ring member in xed positioncorresponding to a predetermined angle of lead of said grooves, andfreeing said ring member to adapt said vprojectile for operation with adifferent angle of lead of such grooves,

- 7. In a projectile having a plurality of recesses in the surfacethereof at spaced intervals around the projectile, a ball in each ofsaid recesses, said balls extending outwardly from the surface of th'eprojectile a distance sufficient for engaging spiral grooves in the boreof the gun, and a frangible means connecting each ball with theprojectile and adapted to be broken upon insertion of the projectile inthe gunbore with the balls yin said grooves.

8. A projectile having a plurality of recesses in the surface thereof atspaced intervals around the projectile, balls in said recesses, saidballs having from approximately one-half to two- Vthirds of theirdiameter extending outwardly .from the surface of the projectile forengaging `spiral grooves in the bore of a gun, and frangible meanssecuring said balls in said recesses and adapted to be brokenuponinsertion of the projectile in. the gun bore withrthe balls in saidgrooves. SOLIS MYRON ZANDMER.

REFERENCES CITED UNITED STATES' PATENTSy Number Date 1 Name 791,679Edmonds June 6, 1905 849,015 Ohl" Apr, 2, 1907 1,184,343 `Gruyer 1 May23, 1916 1,227,889 Cox May 29, 1917 v1,602,037- f Mixsell Oct. 5, `19261,721,704 Mada-Schi July 23, 1929 2,264,791 Fries Dec. 2, 1941 u jFOREIGN APATENTS Number Country Date 184 Great Britain J an. 3,' 18966,940 Great Britain Apr. 12, 1900 20,336 Great Britain 1903 20,782 GreatBritain Nov. 2, 1893 28,934 France Jan 22, 1925 (Addition to 495,517)

